Hydrazines find a variety of uses in silver halide photography. They have been used in negative working surface latent image forming silver halide emulsions to increase speed and/or contrast. They have been used in direct positive internal latent image forming emulsions as nucleating agents. When incorporated in photographic elements as opposed to processing solutions hydrazines are frequently substituted with a group for reducing their mobility, such as a ballasting moiety or a moiety for promoting adsorption to silver halide grain surfaces. In one commonly employed form hydrazines take the form of arylhydrazides which contain a substituent for promoting adsorption to silver halide grain surfaces. Arylhydrazides containing adsorption promoting moieties are illustrated by Leone et al U.S. Pat. Nos. 4,030,925 and 4,031,127, Tsujino et al U.S. Pat. No. 4,245,037, Mifune et al U.S. Pat. No. 4,243,739, Leone U.S. Pat. No. 4,276,364, Research Disclosure, Vol. 151, November 1976, Item 15162 (note reduction sensitization, page 77, left column), and Sidhu et al Research Disclosure, Vol. 176, December 1978, Item 17626. Research Disclosure and Product Licensing Index are publications of Industrial Opportunities Ltd.; Homewell, Havant; Hampshire, P09 1EF, United Kingdom.
It has been suggested from time to time to employ heterocyclic quaternary ammonium salts as nucleating agents in direct positive emulsions. Heterocyclic quaternary ammonium salts employed for this purpose are illustrated by Lincoln et al U.S. Pat. Nos. 3,615,615 and 3,854,956, Kurtz et al U.S. Pat. Nos. 3,719,494 and 3,734,738, and Baralle et al U.S. Pat. No. 4,306,016.
Adachi et al U.S. Pat. No. 4,115,122 discloses heterocyclic quaternary ammonium salt compounds which are propargyl or butynyl substituted. Such compounds are disclosed to be among those satisfying the following structure: ##STR1## wherein
Z represents an atomic group necessary for forming a 5- or 6-membered heterocyclic nucleus,
R.sub.1 represents an aliphatic group,
R.sub.2 represents a hydrogen atom or an aliphatic group,
R.sub.3 and R.sub.4, which may be the same or different, each represents a hydrogen atom, a halogen atom, an aliphatic group, an alkoxy group, a hydroxy group, or an aromatic group,
at least one of R.sub.1, R.sub.2, R.sub.3 and R.sub.4 represents a propargyl group, a butynyl group, or a substituent containing a propargyl or butynyl group,
X.sup..crclbar. represents an anion, and
n is 1 or 2, with n being 1 in the case that the compound forms an inner salt.
Some of the compounds satisfying formula I have been found to be highly effective nucleating agents in direct positive emulsions.
Dersch U.S. Pat. No. 3,255,013 discloses that condensation products of an alkylene oxide and 1,4-di-isobutyl-1,4-dimethylbutynediol are capable of producing speed increases similarly as alkylene oxide sensitizers, but do not require the special antifoggants usually employed in combination with alkylene oxide polymers and their condensation products.